1. Field of the Invention
The present invention relates generally to electrical wiring devices, and particularly to illuminated electrical wiring devices.
2. Technical Background
The typical electrical distribution system includes one or more branch electrical circuits connected to a panel breaker disposed at a convenient location in the structure. The breaker panel terminates the AC power service provided by the power utility and distributes AC power to the aforementioned branch electric circuits installed within the structure. The size of the breaker panel may vary depending on whether it is disposed within a residence, commercial building or some other such facility. Branch electric circuits typically include a series of “daisy-chained” electrical wiring devices, such as receptacle outlets, GFCIs, switches, etc.
The electrical wiring devices are provided in electrically non-conductive housings that include hot and neutral line terminals, configured to be connected to the electrical wiring coupled to the breaker panel, and hot and neutral load terminals. The non-conductive housing electrically insulates the line terminals from the load terminals. The load terminals are connected to downstream wiring that is configured to propagate AC power to one or more downstream electrical loads. The load terminals may also be referred to as “feed-through” terminals. The housing is configured for mounting in an outlet box disposed in the branch electric circuit, or, alternatively the housing itself is the final enclosure such as for self-contained wiring devices, multiple outlet strips (MOS), raceway, extension cords, or power adapters.
Certain types of faults are known to occur in branch electric circuits and electrical wiring systems. These faults represent serious safety issues that may result in fire, shock or electrocution if not addressed properly. Accordingly, each branch circuit typically employs one or more electric circuit protection devices. Protective devices employ a circuit interrupter disposed between the line terminals and the load terminals. The circuit interrupter provides power to the load terminals under normal conditions, but breaks electrical connectivity when the protective device detects a fault condition in the load circuit. There are several types of electric circuit protection devices including ground fault circuit interrupters (GFCIs), ground-fault equipment protectors (GFEPs), arc fault circuit interrupters (AFCIs), transient voltage surge suppressors (TVSSs) and surge protective devices (SPDs). This list includes representative examples and is not meant to be exhaustive. Some devices include combinations of GFCIs, AFCIs and SPDs.
As is commonly known, receptacle outlet wiring devices include duplex receptacle outlets that accommodate electrical power plugs. This includes receptacle outlet wiring devices provided with a circuit protection device, a switch, a sensor or some other feature. The plugs, of course, are connected to a portable electrical load by an electrical cord and provide AC power thereto. Examples of such portable electrical loads include vacuum cleaners, hairdryers, lamps, televisions, electronic devices, appliances, etc.
One issue that is of great concern relates to the visibility of a GFCI or receptacle outlet. Electrical outlets are often disposed a little more than a foot from the floor in many installations making them difficult to locate when the face cover matches the wall surface. In other situations, items of furniture or other such things may partially obscure an outlet, again, making it difficult to locate. In another scenario, the amount of ambient lighting in a given area or room may be at a relatively low level.
Of course, one can think of any number of situations wherein it is desirable to locate and use an outlet when the level of illumination in a room is low. For example, a parent may wish to enter a children's bedroom to plug in a night light, a vaporizer or some other such device without having to turn the overhead light ON. In another example, one may wish to plug a portable electrical load into a wall socket in an area where the lighting is purposely kept at a low level, such as a photographic dark room, movie theatre, etc. In each of these instances a person must first find an available electrical outlet, that is, one that is not in use, in a suitable location. Once this is accomplished, the person must align the blades of the plug with the receptacle openings before inserting the blades into the openings. Of course, if the space is darkened, the process may not be performed without a good deal of fuss and bother.
In another scenario, an electrical fault condition may occur, tripping a circuit interrupter disposed in either a wall mounted GFCI device or in the breaker panel. Of course, the tripping action would result in the electrical outlets in the branch circuit being deenergized. As noted above, some fault conditions may result in fire. It may be beneficial to provide a visual indication that an outlet or a series of daisy-chained outlets were deenergized.
In one approach that has been considered, a neon light bulb has been disposed with the receptacle face to provide illumination. One drawback to this approach relates to the amount and quality of the illumination provided at the receptacle face. An intensely bright image of the energized neon light, that is, a so-called “hot spot,” is visible on the exterior surface of the receptacle face. One unintended consequence of this arrangement is that it makes the receptacle openings difficult to find because they are masked by the hot spot. Of course, hot spots are not aesthetically pleasing and tend to annoy after awhile.
What is needed is an aesthetically pleasing illuminated receptacle outlet that may be easily located within a darkened room or area. What is also needed is a wiring device configured to direct illumination into a set of receptacle openings without generating a hot spot, allowing the user to align the plug blades with the receptacle openings without any additional ambient lighting. What is further needed is an illuminated wiring device that indicates, at a glance, whether or not the device is energized or deenergized.